Compasses.



o. 855,120. Y -PATENTED MAY 28, 1907. v

Y M. C. MHLBACH.

GOMPASSES APPLICATION FILED JAN.`28. 1907.

CO0. MWI/ MAX C. MHLBACH, OF NEWPORT NEWS, VIRGINIA.

COIVIPASSES.

No. 855, 120. i

Specification of Letters Patent.

Patented May 28, 1907.

Application filed January 28, 1907. Serial No. 354,355.

following is a clear, 'ull, and exact description.

This invention relates to compasses, and has for an object to produce aninstrument of this character that can be utilized for the purpose offorming spirals, and the like, a further object being to produce aninexpensive device as well as an elicient one.

To these and other ends which will hereinafter appear, my inventioncomprises the novel features of improvement and combination andarrangement of parts which I will now proceed to describe and inallyclaim, reference being had to the accompanying drawing, forming parthereof, wherein Figure 1 illustrates my improved compass inside-elevation; Fig. 2 is an end view thereof broken away and partly vinsection; Fig. 3 is an enlarged central vertical sectional detail view ofthe tubular members of my improved compass and shows the .adjustable legtherein 5 Fig. 4 is an enlarged central vertical sectional detail viewof the marking arm, wherein a spring is used to force the adjustable legoutwardly; and Fig. 5 is a diagrammatic view of a spiral, which will beused to aid in the explanation of the use of my improved compass Similarnumerals indicate corresponding parts in all the views.

Referring to Fig. 1 in the drawing the numerals 1, 2, 3 indicaterespectively, the pivotal leg, the radially movable marking` arm, andthe radially adjustable positioning arm. The arm 3 is composed of thehinged members 4 and 5 and radius-bar 10, the member 5 being tubular andslidably supporting the leg 6 which, at its lower end, is provided witha needle point 7 suitably held, as shown, in the ordinary way. To holdthe leg 6 rigid an adjusting screw 8 is herein employed. The members 4and 5 are hinged together at 9 in any suitable manner, and the member 4is' hinged to a radius-bar 10, at 11. The radius-bar 10 is provided witha hub 12, which is rotatably fitted to the reduced upper portion 13 ofthe stationary or pivotal leg 1. The said le 1, has attached, as at 14,a manipulatingnob 15 by which the said pivotal leg is rotated. Themarking arm 2 comprises the hinged members 16 and 17, which are suitablysecured together, as at 18. The member 17 of the said marking arm 2 ispivotally connected, as at 19, to the said pivotal leg 1 and is alsoprovided with atoothed rack 20.. The pencil-holder 2l is slidably fittedto the tubular member 16 and is kept against the paper or any otherelement upon which a design is to be drawn, by the spring 22 (see Fig.4). To actuate the arm 2, I employ a train of gears which communicateradial movement to the said arm 2 when the pivotal arm 1 is rotated bythe knob 15. The rack 20 which is carried by the arm 2, has meshedtherewith the gear 23, which is pivoted to `the leg 1. The gear 23 inturn meshes with a pinion 24 which is carried, or actuated by the gear25 which, like the gear 23, is pivotally attached to the leg 1. The gear25 in turn meshes with the pinion 26, carried by a bevel gear 27pivotally attached tothe leg 1. To the radius-bar 10 I attach abevel-pinion 28 which meshes with the bevelgear 27 and acts as an anchorfor the rest of the train, the said gear 28 always remaining stationary.The adjustable anchor-arm 3 is for the purpose of holding the saidbevel-pinion 28 stationary. When the arm 2 is performing its function,it will pass between the leg 1 and the arm 3; consequently it isnecessary that the said arm 3 should be radially adjustable in orderthat the arm 2 can describe designs of various diameters. The arm 3 alsoserves to locate the instrument.

In the event of describing a spiral, as in Fig. 5, for instance, theneedle point 7 -would be placed on the center line 29, as indicated at30. ated by the gears carried by the pivotal arm 1. Referring to Fig. 5,and presuming I wish to make this design, or spiral, I place the pivotalleg 1 at 31, the arm 2 being at theV point 32 between the leg 1 and thearm 3, which is positioned at some point outside of the design, as at30, as has been mentioned. I then, by means of the knob 15, rotate theleg 1 in the direction in which I wish the spiral to go, as, forinstance, in the direction of the arrow Fig. 5. As the arm 2 is carriedby the leg 1, it will follow a circular path, but owing to the gears,connected as hereinbefore mentioned, the varm 2 is caused to graduallymove outwardly from the center 31. The gear 28,

vwhich is carried by the bar 10, serves as an anchor; in other wordswhen the leg 1 is rotated, the gears and arm 2 are carried with it.

It is obvious that the arm 2 is actu- IOO IIO

As the arm 3 is fixed, likewise the gear 28, the said gears pass aroundthe gear 28, in the manner of a sun-and-planet construction.

The distance between the convolutions of the spiral depends upon theproportion of the gears to one another 5 consequently after havingascertained the spiral I want, I then put 1n gears of the properproportion. In order to form a design, I place in gears so proportionedas to carry the arm 2 outwardlyT in the proper proportion when the leg 1is rotated.

Having now described my invention, what I claim and desire to secure byLetters Patent 1s:

l. A compass, comprising a pivotal member, a radially adjustablepositioning arm, rotatably mounted thereupon, a radially movable armcarried by said pivotal member and adapted to carry a marking element,and means adapted to cause said radially movable arm to gradually moveaway from the pivotal member when said pivotal member is rotated. f

2. A compass, comprising a pivotal member, a radially adjustablepositioning arm, rotatably mounted thereupon, a radially movable armcarried by said pivotal member and adapted to carry a marking element,and means carried by said pivotal member and actuated by said radiallyadjustable positioning arm adapted to cause said radially movable arm todescribe a spiral when said pivotal member is rotated.

3. A compass, comprising a pivotal member, a radially adjustablepositioning arm, rotatably mounted thereon, a radially movable armcarried by said pivotal member and adapted to carry a marking element, atrain of intermeshing gears carried by said pivotal member and actuatedby said radially adjustable positioning arm adapted to cause saidradially movable arm to describe a spiral when said pivotal member isrotated.

4. A compass, comprising a pivotal member, a radially adjustablepositioning arm, rotatably mounted thereon, a radially movable armcarried by said pivotal member and adapted to carry a marking element, atrain of intermeshing gears carried` by said pivotal member, a gearcarried by said radially adjustable positioning arm., adapted to meshwith one of said train oi gears, whereby said train of gears is operatedwhen said pivotal member is rotated, and means operated by said train ofgears adapted to operate said radially movable arm.

5. A compass, comprising a pivotal member, a radially adjustablepositioning arm, rotatably mounted thereon, a radially movable armcarried by said. pivotal member and adapted'to carry a marking element,a train of intermeshing gears carried by said pivotal member, a gearcarried by said radially adjustable positioning arm, adapted to meshwith one of said train of gears, whereby said train of gears is operatedwhen. said pivotal member is rotated, and a toothed segment carried bysaid radially movable arm adapted to mesh with one of said train ofgears.

6. A compass, comprising a pivotal member, a radially adjustablepositioning arm, rotatably carried thereby, a radially movable markingarm pivotally mounted on said pivotal member, and means adapted. to movesaid marking arm outwardly when said, pivotal member is rotated, saidmeans comprising toothed elements actuated by said positioning arm.

7. A compass, comprising a pivotal member, a radially adjustablepositioning arm rotatably carried thereby, an arm pivotally mounted onsaid pivotal member and adapted for an outward movement in a verticalplane, a tubular member pivotally mounted on said arm, a holderadjustably mounted in said tubular member and adapted to receive amarking element, a train o'f gears adapted to operate said verticallymovable arm, and a gear carried by said positioning arm adapted tooperate said train of gears.

Signed at Newport News, V a., this 23rd day of January 1907.

'MAX C. MUHLBACII. Witnesses:

PETER LAZAnIon, GODFREY KINDER.

